Auditors say they have found overpayments for medical expenses in Washington's Medicaid system.
A performance audit released Monday by State Auditor Troy Kelley's office examined 2010 payments by two insurers that cover most of the hundreds of thousands of Washingtonians enrolled in the state's Medicaid managed-care program for the poor: Community Health Plan of Washington and Molina Healthcare of Washington.
Looking only at a few categories of claims selected based on risk, they estimate the insurers overpaid medical providers by $17.5 million for those categories.
Insurers in the program pay roughly $1 billion a year to providers. But auditors couldn't say for sure if the total payments were greater because of the errors. If so, that would have raised the premiums the state paid to the insurers starting in 2013.
Weaknesses in state oversight contributed to the errors, Kelley's office found. The state Health Care Authority doesn't have a comprehensive system to review costs.
In a response, the Health Care Authority questioned auditors' estimate of overpayments but said it will develop a comprehensive monitoring system. That will take time, the agency said. A committee will develop a plan by the end of the year with time and cost estimates, it said.
The managed-care program includes most of the people on the state's Medicaid rolls, which are growing dramatically this year as the Affordable Care Act takes effect.